Biological activities and variation of symbiotic fungi isolated from Coral reefs collected from Red Sea in Egypt.

Ten specimens of coral reefs were collected from the Red Sea in the Ein El-Sukhna region. Fungal isolation was done using two media, Dextrose Yeast Extract Agar (DYA) and Rose Bengal Agar (RBA). The morphological traits identified 18 fungal isolates belonging to the phyla Ascomycota, Mucoromycota and Deuteromycota. Five genera in three orders have been isolated: Eutrotiales ( and ), Mucorales () and Moniliales (). The heat mapping clustering of the isolated fungi declared that and were the most frequently isolate fungi in coral reefs. It was found that colonised eight coral samples with 80% colonisation rate. Moreover, about 50% of the isolated fungal species were specific to one coral reef only such as and isolated from only, and from from and from from and and from . Biological activities (antimicrobial, antioxidant antiradical and cytotoxicity) of the most predominant fungal species were investigated. The antimicrobial activity of coral fungal filtrates were investigated against six pathogenic bacteria including ATCC11775, ATCC19424, ATCC10145, ATCC19433, subsp. ATCC25923, subsp. ATCC6633 and two pathogenic yeast including ATCC7102 and ATCC22019. Most of these fungal filtrates exhibited moderate to high antibacterial activities against both gram positive and gram negative bacteria, however it showed relatively low bioactivity towards the pathogenic species. Investigating the free radical scavenging activity using DPPH reagent showed low to moderate bioactivities. The highest cytotoxic activity against liver cancer cell line Hep-G2 with an IC values of 18.8 µg/ml was exhibited by MN083316 and a metabolomics study was done on the ethyl acetate extract of this strain using LC-ESI-MS fingerprints leading to the isolation and purification of compound . Using 1D and 2D NMR techniques compound was identified as ditryptophenaline. Compound exhibited a strong antimicrobial, antioxidant activities as well as cytotoxic activities against MCF-7 and HEPG2 with IC values of 5.8 and 7.6 mmole, respectively. The objective of this study, isolation of Coral-reef associated fungi and studying their biological activities to produce the most active secondary metabolite which might possess a novel biological activity.